Since I would be dogsitting soon, I whipped up this seat cover, hammock style. This is great because it keeps the pups from getting into the front seat and if I have to stop quickly they won't fall to the floor.
It is made with fleece and a sturdy twill on the back. You could use canvas or anything sturdy, really. I used cotton strapping with buckles to attach it to each of the four headrests and it seems to work out great!! I love that I can just toss it in the wash when needed and it seems to trap all the hair and droll in one place!